The objective of this supplement to the program project, Microelectronics Laboratory for Biomedical Sciences (GM 14267-11) is to carry the development of research devices beyond feasibility studies in the laboratory environment to include animal testing and clinical evaluation. This will lead to possible early acceptance by the biomedical research community and acceleration of transfer to the medical instrumentation industry. This supplement contains three projects: (1) Pilot production of pressure transducers: The pilot production of the designed miniature, absolute pressure transducer of the size 8 X 50 X 150 mils is proposed to provide units for (a) thorough characterization of the device, (b) development of packaging techniques for its use as an indwelling pressure sensor, and (c) obtaining information on yield and fabrication techniques to be transferred to industry. (2) Fabrication and evaluation of intracranial pressure monitoring systems: Using the ICP and ICP plus temperature designs, twenty units will be fabricated for evaluation in vitro and in vivo in dogs to define stability and reliability. A protocol will be submitted by the Department of Neurosurgery at Case Western Reserve University to evaluate the systems in humans. (3) Chemical Transducers: Solid state pH sensors, using MOS and FET structures will be designed. Fabrication technology, device characterization, encapsulation methods and on-chip signal processing circuits of the sensor will be studied to provide necessary information to produce the miniature, implantable pH transducer, as well as other solid state ion sensors.